The 100msp for a marketplace purchase is for your very first marketplace purchase ever so if you have made a purchase prior than when you signed up you will not recieve it
http://rewards.xbox.com/rush-for-gold/
Contest starts the 16th of April.
I know for sure it is open to Canadian residents.
Im sure it is open for every country who has xbox rewards.
They are giving away:
:drool:1 000 000 MSP:drool:
:drool:10 Limited Edition Star Wars Xbox Kinect...